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Book/Report | FZJ-2016-04621 |
1981
Kernforschungsanlage Jülich, Zentralbiliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/12263
Report No.: Juel-1744
Abstract: Chapter A: The method of high temperature mass spectrometry with a Knudsen cell (HTM) is compared to other methods for the studyof condensed phases and gaseous compounds. The potential of HTM is described. A complete survey on the reviews in the field ofHTM is given. Chapter B: The systems quadrupole mass spectrometer - Knudsen cell and single focusing magnetic mass spectrometer - Knudsen cell used in this work are described. Chapter C: The vapour pressure measurements of binary and ternary amalgams as well as the experimental methods used are reviewed up to 1975. The vaporization of the solid compounds of the binary systems Mg-Hg (MgHg$_{2}$, MgHg, Mg$_{5}$Hg$_{3}$, Mg$_{2}$Hg, Mg$_{5}$Hg$_{2}$, Mg$_{3}$Hg) and Ca-Hg (CaHg$_{3}$, CaHg$_{2}$, CaHg, Ca$_{3}$Hg$_{2}$, Ca$_{5}$Hg$_{3}$, Ca$_{2}$Hg, Ca$_{3}$Hg) and of the ternary alloys with the composition Hg$_{1}$-In$_{4}$-Mg$_{n}$ (n = o, o.1, o.2 ... 1) is elucidated. It was possible to identify the vaporising species and to determine their equilibrium pressures and the corresponding reactions of evaporation. The enthalpies of formation and the Gibbs free energies of formation of the above mentioned compounds are computed and discussed. For the system Hg-In-Mg the phase diagram was determined in the composition range Hg$_{1}$-In$_{4}$-Mg $_{o-1}$. The vapour pressures obtained over the various amalgams are discussed with respect to their possible use in fluorescent mercury lamps. Chapter D: The dissociation enthalpies of the homonuclear intermetallic molecules Cu$_{2}$, Hg$_{2}$, Cu$_{3}$, Ag$_{3}$, and Au$_{3}$, as well as of the heteronuclear intermetallic molecules DyCu, DyAg, DyAu, TbCu, and HoCu are determined by studying these molecules in the vapour under equilibrium conditions. The dissociation enthalpies derived are discussed. Dissociation enthalpies of the gaseous compounds between the rare earth metals and the elements of the 1B group are predicted. - In addition to thesabove mentioned intermetallic molecules, the ionic molecules NaI, (NaI)$_{2}$, and (NaI)$_{3}$ were studied upon vaporising Nal(s). Enthalpies of dimerization and trimerization were determined. The data derived are of practical interest for metal halide lamps. By applying the Pauling model for alkali halogenides our experimental value for the enthalpy of trimerization could be verified and the trimerization enthalpies and molecular parameters of eight additional alkali halogenide trimers were predicted.
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